Screening apparatus



July 14, 1925.

. M.'P. REYNOLDS SCREENING APPARATUS 2 Sheets-Shet 1 Original i e p 1920' $025 on mo/a atto'zmgb.

July 14, 1925. ='1,545.976

M. P. REYNOLDS SCREENING APPARATUS Original Filed Sept. 3, 1920 2 Sheets-Sheet 2 J0 J5 HAKDNE5$ KEADINC RELATIVK.

II N

Sam f jyor/c 21 25/500 [C no a s Patented July 14, 1925.

\ UNITED STATES PATENT j OFFICE.

MORLEY PUNSHON REYNOLDS, 0F CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO THE A W. S. TYLER COMRQNY, OF CLEVELAND. OHIO, A CORPORATION OF OHIO.

scnnnnine nrrana'rus.

Application filed September 8, 1920, Serial No. 408,091. Renewed December 11,

To all whom it may comer n:

Be it known that I, MORLEY PUNSHON REYNoLns, a citizen of the United States, and a resident of Cleveland Heights, county of Cuyahoga, and State of Ohio, have invented a new and useful Improvement in Screening A paratus, of which the following is a speci cation, the principle of the invention being herein explained, and the best mode in which I have contemplated applying that principle so as to distinguish it from other inventions.

The present improvements, relating, as indicated, to screening apparatus, are more particularly directed to an improved machine for separating and classifying materials in which a more effective vibration, and consequently a more accurate separation and longer screen life are secured. To the accom lishment of the foregoing and relate ends, said invention, then, consists of the means hereinafter fullydescribed and particularly pointed out in the claims. I

The annexed drawing and the following description set forth in detail certain mechanism embodying the invention, such disclosedmeans constituting, however, but one of the various mechanical forms in which the principle of the invention may be used.

In said annexed drawing Fig. 1 is a longitudinal vertical section through an inclined screening machine, in which my invention is embodied; Fig. 2 is a plan view of a woven wire screen and mounting therefor; Fig. 3 is a transverse section through one side of such screen and mounting; Fig. 4 is an enlarged plan 'view of the screen alone; and Fig. 5 is a chart showing diagrammatically the relative hardness of the wires in my screen.

The inclined screening. apparatus at present in most general use consists of an inclined framework in which a woven wire screen is mounted, also in an inclined position, with its inclined or longitudmally ex-- tending edges attached to the frame and its upper and lower (transverse) edges free.

The screen has usually been vibrated by.

tened along all edges to a frame and then vibrated or shaken.

My invention is here illustrated and described in connection with an inclined screening machine. 7

In Fig. 1, I have shown an inclined screen 1, (frame not shown), consisting of a supportlng frame 2 mounted in an inclined position with its upper end resting upon .supports 3. The framework upon which the woven wire screen is mounted consists of two parallel longitudinal frame-members 4 which are connected by end members 7, a

means of tension rods 12, of which there are usually three or four in the ordinary screen frame, which have right and lefthand threaded adjustment in sockets 13,

carried on the two frame members.

Mounted above the screen 8 is a vibrating device which is usually carried upon the casing surrounding and enclosing the screen. This vibrating device consists of an electromagnet 14, operating an armature 15, which is attached directly to the screen edge by means of a U-sha ed bridge 16 and a resil ient vibrating strip 17, the latter being disposed longitudinally and centrally along the screen. The action of this vibrating apparatus is to pull up the armature, carrying the screen with it, and then jarring the same at the upper limit of the armatures movement. This jar is transmitted to all portions of the screen surface through the bridge 16 and the resilient strip 17. The result of this action is to vibrate the screen surface between its lateral edges, and it must be remembered that the top and bottom edges of the screen surfaces are entirely free. It is therefore the wires which extend transversely of the inclined screen which are .in vibration, the longitudinal wires being vibrated to' a very much less de ee than the transverse wires.

Fi s. 2 and 4, I have shown the screen 8. In ig. 2 the screen 8 is shown as it is formed ready for application to a screening machine, and having the hook strips 10 secured to either longitudinal edge and the resilient vibrating strips 17 v secured centrally along the screen.

In F ig..4, I have shown an enlarged plan 'view of a woven wire screen consisting of the longitudinally extending wires 18 and the transversely extending wires 19. My invention is based upon an analysis of the vibratory action of a woven wire screen when mounted as previously described in an inclined screen rame under the action of a vibrating device of the ty e described. I have found that a very Inuc tive vibration can be secured in such a machine if the transverse wires, which areunder a uniform vibratory tension, are formed of a hard, highly resilient wire. It is immaterial as to whether the longitudinal wires, which are not in tension, and which are not vibrated to any great extent, are formed of resilient or non-resilient wire, and any suitable weaving wire may be used for this pu os'e. The screen may be woven in any of t e usual ways, so long as when applied to the inclinedframe it has hard highly resilient transverse wires.

The resiliency and degree of hardness of the transverse wires is essential to secure the most effective vibration of the screen, but on the other hand there is another limit to the hardness of these wires which cannot be exceeded without being destructive to the wire screen. It will be seen, therefore, that any hard, highly resilient wire will not satisfy the requirements of such a machine as the degree of hardness of these wires must be confined between certain definite limits. In order to accurately define the limits of hardness and resiliency between which the hard wires must range to be efi'ective in such a screen I have shown in Fig. 5 a chart, in which there is iven diagrammatically the limits referre to. In this chart the diameter of the wire has been plotted vertically and the hardness readings have been plotted horizontally. These hardness readings have been made on a Rockwell hardness testing machine, which is a machine having an indenting device actuated by a given load to indent metal articles, after which the depth of the indentation is measured, and is translated into a number indicating the hardness of the particular specimens tested.

On the chart I have shown firstv a curve A marked soft annealed which is drawn from a large number of determinations on the Rockwell machine of the hardness of different samples of soft annealed wire of various diameters. I have also shown two curves marked B and C, of which the curve B was made from a lar e number larly drawn after plotting the relative hard-- ness readings on a Rockwell machine of a large number of specimens of wire which had the highest degree of hardness that would permit them to be used to secure the desired results in the present machine. Any wire whose hardness is between the limits indicated by the curves C and 9B is of the proper hardness for the transverse wires of my improved machine. Thus, for example, if a specimen of wire having a diameter of nine-hundredthsof an inch were to be tested to determine its hardness, and hence, whether it could be used in the present machine, if its hardness lay anywhere between 26. and 51 on the Rockwell machine it could be used. Above and below these two limits the wire would be either too hard or too soft.

To state the condition and character of the hard resilient wires in another way I have determined the tensile strength of a large number of samples of wire which may be used for the hard highly resilient transverse wires in my machine. In the following columns I have given, first, the diameter of the wire in inches; in the second column, the limits of tensile strength between which the breaking strength of the wire must fall if it may be used as the hard transverse wire, and in the third column, the actual breaking strengths of soft annealed wire of various diameters.

Tension required to break wires.

[Pounds.]

Hard wire Soft Di *it'ifi arne er c (inches). Limits- It is well known that the tensile strength of wire varies directly as the hardness, and that a hard wire has a considerably higher nteaeve tensile strength than a soft annealed wire of the same size and material. Thus, in the tables given above, soft annealed wire having adiameter of ninety-two thousandths of an inch has an actual breaking strength of 460 pounds. Hard wires of the same diameter, and of a hardness suflicient to permit these wires to be used as'the hard transverse wires in my machine, have a tensile strength falling between 790 and 1600 pounds. That 1s, the lowest limit which is ermissible for the tensilestren h of the ard wire'is almost twice the ten e strength of a soft annealed wire of the same diameter. 1

Because of the extreme hardness of the wires which are tensioned in the present screen, it is essential that the edge portions of these wires be softened enough to rmit of the continued vibration and ben ing back and forth of these wires which is' experienced in the action of the screening apparatus. After the screen has been woven and before it is applied to the hook-strips or otherwise fastened to the frame, the two transverse ed es are annealed or softened until the condition of the wires at the edges is in a soft annealed condition. In this way the edges of the hardened wire are secured in the body of the screen without the.

disadvantage of the early breakage of the wires at their point of attachment to the screen frame.

In my machine described above, it has been found that a remarkable change in the character of the vibration is effected, with the result that the machine has a considerably increased ca acity. A screen provided with high] resilient transverse wires, maintens1on,

tained un er a uniform, vibrato can be'vibrated very much more lyunder the same intensity of im ulses than screens otherwise mounted, an the screen is livelier and shows very much less tendenc to clog or Fblind when working on di cult materials.

Other modes of applying the principle I therefore partlcularly point out and distinctly claim as my invention 1. In screening apparatus, the combination of an inclined screen-receiving frame,

a woven wire screen mounted in said frame, Stlld frame beingl provided w1th means tens1on1ng all of t e transverse w1res of said screen to a uniform vibratory tension, said screen having hard resilient transverse wires, and means adapted to vibrate said screen.

2. In screening apparatus, the combination of an inclined screen-receiving frame, a woven wire screen mounted in said frame, said screen bein provided with hard resilient transverse y extending wires, means on said frame adapted to erfgage all of said transverse wires and tension the same to a uniform vibratory tension, and means adapted to vibrate said screen.

e 3. -In screening apparatus, the combination of an inclined Screen-receivin frame, a woven wire screen mounted in sai frame, said screen bein provided with hard resilient transverse v extending wires engaged at their ends by said frame and maintained at a uniform vibratory tension, and the longitudinal wires of said screen being free, and means adapted to vibrate said screen.

Signed by me, this 26th day of August, 1920.

MORLEY Punsnon REYNOLDS, 

